Tuning mechanism



Nov. 14, 1944-.

L. J. FICHTER Ein-A1. 2,362,690

TUNING MEGHANISM Filed Oct. 21, 1942 7U SPIA/(IR 6, l@

Gttomegs Patented Nov. 14, 1944 TUNING MECHANISM Ludwig' J. Fichter, Dayton, Ohio, and Bertram A. Schwarz. Kokomo, Ind., assignors to Genera'i Motors Corporation, Detroit, Mich., a corpora tien oi' Delaware Application October 21. 1942, Serial No. 462,832

Claims.

rI'his invention relates to indexing means and more specifically to means to index to definite predetermined angular positions a rotatable member by the closure of certain switch means. Present day constructions frequently require the use of indexing means for various purposes such as machine tools, radio receivers, land other apparatus. In these constructions it is necessary to provide automatic means to bring movable members to set positions upon the simple actuation of a reciprocating rod or switch member. This is particularly true in the application of so-called push button or automatic tuners on radio receivers, although this is only one specialized application of our present invention.

It is therefore an object of our invention to provide indexing means for bringing a mechanical part to a predetermined position which may be operated by a minimum of movement of translationally movable push buttons.

It is a further object of our invention to provide an indexing means capable or moving to a plurality of different positions and controllable by a plurality of diierent push buttons.

It is a still further object of our invention to provide indexing means automatically operable to accurately adjust desired parts.

It is a still further object of our invention to provide indexing means capable oi' bringing a rotatable means to different angular positions controlled by a plurality of push button switches.

With these and other objects in view which will become apparent as the specification proceeds, the embodiments of our invention will be best understood by reference to the following specification and claims, and the illustrations in the accompanying drawing, in which:

Figure 1 is a schematic showing of a system embodying our invention; and,

Figure 2 is a schematic showing of a modilication of a portion thereof.

There are of course a number of different ways iny which members can be automatically moved to predetermined positions and particularly means to tune resonant circuits in a radio' receiver so that the same will be receptive to different transmitting stations. One of these indexing means of the so-called drum type is shown in a conending application Serial No. 394,071 filed May 19, 1941. in the names of Fichter and Kaegi and entitled Tuning mechanism in which a rotating drum carries a series of radially projecting members to do the actual tuning. Since the drum per se forms no part of the present invention, it is only shown as a circular drum and it will not be necessary to describe the samev here in detail. but let it suffice to say that th: rotating drum carries the necessary nal indexing means and the present invention is concerned with means for rotating the drum.

Referring now more specitlcaily to Figure 1, there is shown therein a rotating drum 2 which, as just mentioned, carries the adjustable indexing means at different angular positions. On the end of this drum there is mounted a circular conductive ring 4 and also a ratchet gear B, the latter being secured to the shaft 8 and rotating with the drum about this axis. Fixedly mounted adjacent the periphery of the drum and spaced at arcuate distances from each other are a series of conductive brush members i0, i2, i4, IB, I8 and 2B adapted to contact the ring 4. These are supported by the surrounding frame. They extend to the conductive ring 4 and at substantially all points conduct current to this ring. Each of these conductive brush members is connected by lines 22, 24, 26, 28, and 32 to a series of springbiased contacts 34, 3B, 38, 40, 42 and 44, respectively. Cooperatlng with each of the last-mentioned spring contacts are a series of stationary contacts 4B, 48, 50, 52, 54 and 56, all of which are connected to line 58 and thus to one terminal of a battery or other sourceoi power.

These various switch assemblies are mounted adjacent a series ci reciprocating plungers 82 which are actuated by a series of push buttons 84 which @1t-end through the front panel of the supporting casing. Each of these push buttons is provided with an enlarged head and a smaller throat which latter extends through a plurality of openings 66 in a plate 65 extending the full length of the push button assembly, One end of this plate carries a contact 68 which moves therewith and cooperates with fixed contact 10 which is connected by line 12 to the speaker oi the receiver. Thus when any push button is depressed, the plate will be moved inwardly to close the switch 68--10 and short out the speaker so that no sound may issue therefrom during the tuning operation. f A

The throat of each push button 84 also carries a small pin 14 which is adapted to be forced into a V groove formed between two adjacent sections of slide members 16 which extend the full width of the tuning unit and are kept in alignment by two stationary blocks 18 at each end thereof. There is just enough clearance between all of these slidable units 16 to allow one pin 14 to proceed to its full inward position and when in this position, as will be evident from the drawing, none of the other pins 14 can be pushed inwardly to their fullest degree as the notch at this point will be closed and prevent such action, Thus only one push button at a time can be forced to its i'ull position, the slides providing lock-out means.

Supported on the central section of each of the reciprocating pins 62 is a magnetic sleeve 80 which 'when the reciprocating assembly is in its outer position is ofi center between the two arms 82 and 84 of an electromagnet which is provided with energy from an energizing coil 00. When, however, the reciprocating push button assembly has been forced inwardly, the magnetic sleeve moves to a position bridging the arms and provides a path of low reluctance for the flux between the arms of the electromagnet and the push button assembly is maintained in this position by the energization of the coil 00, all oi' the assemblies operating in the same manner and the one being depressed only being maintained in its inward position as long as the. coil is energized until the device has reached its tuned or indexed position. The coil 00 is deenergized, as will be explained, and there is suilicient strength provided in each spring 00 supporting the series of movable contacts 04, 00, 30, 40, 42 and 44 to force the contacts apart and the reciprocating push button assembly back out to its deenergized position.

There is also supported adjacent the drum in a stationary manner a brush assembly 90 which engages the conductive ring 4 in all angular positions of rotation oi' the drum` This brush is connected by line 02 to one terminal of the electromagnet 80, the opposite side of which is grounded. It is also connected to a line 04 which terminates in movable contact member 00 carried by a reciprocating member 00 to cooperate with a stationary contact |00. The latter contact is connected by line |02 to one terminal of an electromagnet |04, the opposite terminal of which is likewise grounded. Reciprocating member 00 is mounted in a stationary part |00 which has a spring-biased pin |00 projecting toward the reciprocating member 90 and cooperating with a small projection ||0 to maintain the reciprocating member in either of its extreme positions. The member 00 also has two projecting arms |I2 and ||4 between which oscillates a lever ||0 carried by the reciprocating core 0 of the solenoid |04. I'hus as the core ||0 moves upward and downward, the lever ||0 will contact either projection ||2 or ||4 to also move the reciprocating member 00 to open and close the switch formed by contacts 00 and |00.

A lever is pivotally connected t0 the top of the core ||0 and is spring-biased upwardly by connection to a coiled spring |22, the opposite end of which is secured to the case. Also pivoted to the upper end of the lever |20 is one end of a lever |24, the opposite end of which is pivotally supported upon the shaft 0. This lever |24 carries a pawl |20 which cooperates with the teeth of the ratchet 0. In the outer surface of the conductive ring 4 is provided a notch |20 which is just large enough to accommodate one end o! any one of the brushes |0, |2, |4, |0, I0 and 20 so that at one angular position one of these brushes will not make contact with the ring 4, thus breaking the electrical circuit. Brush 00, however, overlies practically the whole width of this ring and therefore remains in electrical contact at all times therewith.

There are shown in this illustration sixpoints at which the rotating indexing drum may be set and of course there are provided an equal number of push buttons to bring the same to these positions. The number of course is not important as any number may be provided, depending upon the desire of the designer.

In the operation of the device one of the push buttons is initially depressed and let it be assumed that the one shown in Figure l is the one selected. This movement closes the switch contacts 04 and 40 and if the drum is in any other position than that shown, a circuit will be completed to the operating solenoid |04 through the following circuit: battery 80, line 00, contact 40, contact 04, line 22, brush I0, conductive ring 4, brush 00, line 92, line 94, contacts 00 and |00, line |02, solenoid |04 to ground. At the same time of course a circuit is completed through the hold-in solenoid 00 and the push button assembly is then maintained in its illustrated position. The solenoid |04 will then be .energized to pull its core downwardly and cause the ratchet to move the drum the distance of one tooth. In so doing the arm ||0 will contact the arm ||4 to move the reciprocating member 00 down past the springbiased pin |00 and break the switch 00-|00. The coil |04 is then deenergized and the spring |22 will at once withdraw the core ||0 and return the ratchet assembly to its upper position. If the brush |0 has not reached the position of the groove |20, the operation will be repeated step by step until it reaches the point shown on the drawing. At this time the circuit will be broken; the solenoid will be deenergized; and the push button 04 will be allowed to return to its outermost D0- sition through the force of the associated spring 00. The operation of any of the other push but tons will of course be identical to that just described. As previously mentioned, the depression of any of these push buttons will mute the speaker through the operation of the short circuiting switch 00-10 and mechanically lock out any other button.

Figure 2 shows a modified form of ratchet mechanism and drive in which the rotation of the drum about its axis is slower. In Figure l each actuation of the ratchet mechanism rotates the drum approximately However, if we wish to move the drum more slowly, this may be accomplished by the device as disclosed in Figure 2 in which there is shown, as before. a rotatable drum having a plurality of brush members I0, |2, I4, |0, |0 and 20 which only overlie the edge of the conductive ring 4 which as before has a slot |20 therein to break the circuit upon acquiring a definite index. A large bnlsh 00 is also again provided which is adapted to remain in contact with the conductive ring 4 at all times. Figure 1.

In this instance however there is provided a ratchet 0' which has a small number of teeth and this is adapted to cooperate with a pivoted pawl |00 which is carried on the end of a lever |02 which is spring-biased upwardly by a spring |24. The lever |02 is pivoted to a yoke member |00 which carries an operating solenoid |00. The pivoted lever |02 also carries a movable contact point |40 which cooperates with a stationary The associated system is as shown in contactor |42. The circuit from line 02 is through line |44 which is connected to the upper terminal |42. The lower terminal |40 is connected by line |40 to the operatmg solenoid |00. Thus when the circuit is completed through any one o! the brush assemblies I0, |2, |4, |0, I0 and 20, through the conductive ring 4 to the brush 00, current will ow to the operating coil |00 through the brush 00, line 02, line |44, contact |42, contact |40, line |40, solenoid |00 to ground.

The energization of the solenoid will attract the pivoted lever |32 which serves as an armature to ratchet the gear 0' one tooth. In moving downwardly, however, the armature |22 brings with it movable switch contact |40 to break the electric circuit to the solenoid |30 which becomes deenergized and the spring I 24 pulls the armaaaeaeeo ture upwardly again to cause the pawl |30 to ratchet to the next tooth. The upper movement again closes the switch ilo- |42 and the operation is repeated until whichever brush I0, l2, I4, I8, I8 or 2B is connected to the source of power moves into alignment with the slot |28. It is thus evident that we have provided an automatic means for rotating an indexing member to different angular positions controlled by a plurality of different indexing buttons.

We claim:

l. In an indexing system, a rotatable indexing means, ratchet means to rotate the rstnamed means, a circular conductor mounted on the rotatable means having an indexing notch thereon, a plurality of brushes overlying the conductor means adapted to enter the slot at one point, means connecting the switching means formed by the brushes and circular conductor to the ratchet )neans to control the same and a plurality of actuatable means connected to the brushes to close the circuits therethrough and bring4 the indexing means to a predetermined position, dependent upon which of the actuatable means was moved.

2. In an indexing system, a rotatable drum, solenoid-operated ratchet means to rotate the drum, a plurality of stationary brush assemblies mounted adjacent the drum, a circular conductive ring mounted on the drum to cooperate with the brushes, said ring having a cut-away portion whereby a portion of the brushes would not contact the ring at certain points, a source of power and conductors connecting the source of power to the brushes and to the solenoid whereby the drum movement will be controlled by the switches formed of the brushes and the ring.

3. In an indexing system, a rotatable drum, solenoid ratchet means to rotate said drum step by step, a plurality of ai'cuately spaced brush means mounted adjacent the drum, a conductor ring mounted on the drum to cooperate with the brush means and having a cut-away portion, conducting means connected to the brushes, a source of power connected to a portion of said connecting means and the solenoid connected to the other portion whereby the brushes control the energization of the solenoid means to bring the drum to different angular positions.

4. In an indexing means, a rotatable indexing drum, ratchet solenoidmeans to rotate the drum, switching means, a portion of which is mounted adjacent the drum and a portion carried by the drum controlling the solenoid ratchet drive and a second series of switching means connected to the first-named switching means to index the drum.

5. In an indexing means, a rotatable indexing drum, ratchet solenoid drive means for the drum, a conducting ring having a slot therein carried by the drum, a plurality of brush assemblies mounted in spaced relation around the periphery of the drum and engaging the ring but capable of moving into the slot at one angular position, a plurality of push button switches, each connected to one of the brushes, and means connecting the ring to the solenoid drive whereby upon the actuation of a push button to close a switch the solenoid will be energized to move the drum until the brush associated therewith lies in the slot of the ring and the circuit is broken.

6. In an indexing means, a rotatable indexing drum, ratchet solenoid drive means for the drum,

by the drum, a. plurality of brush assemblies mounted in spaced relation around the periphery of the drum and engaging the ring but capable of l moving into the slot at one angular position, a plurality of push button switches, each connected to one of the brushes, means connecting the ring to the solenoid drive whereby upon the actuation of apush button to close a switch the solenoid will-be energized to move the drum until the brush associated therewith lies in the slot of the ring and the circuit is broken, and means for holding the push button means in their actuated position until the desired index has been obtained.

7. In an indexing means, a rotatable indexing drum, ratchet solenoid drive means for the drum. a conducting ring having a slot therein carried by rthe drum, a plurality of brush assemblies mounted in spaced relation around the periphery of the drum and engaging the ring but capable of moving into the slot, at one angular position, a plurality of push button switches, each connected to one of the brushes, means connecting the ring to the solenoid drive whereby upon the actuation of a push button to close a switch the solenoid will be energized to move the drum until the brush associated therewith lies in the slot o! the ring and the circuit is broken, and interlocking means to prevent the closure o! more than one push button switch at one time.

8. In an indexing means, a rotatable indexing drum, ratchet solenoid drive means for the drum, a conducting ring having a slot therein carried by the drum, a plurality of brush assemblies mounted in spaced relation around the periphery f of the drum and engaging the ring but capable of moving into the slot at one angular position, a plurality of push button switches, each conneeted to one of the brushes, means connecting the ring to the solenoid drive whereby upon the actuation of a push button to close a switch the solenoid will be energized to move the drum until the brush associated therewith lies in the slot 0I the ring and the circuit is broken, means for holding the push button means in their actuated position until the desired index has been obtained, and interlocking meansto prevent the closure of more than one push button switch at one time.

9. In indexing means, a rotatable indexing member, step-by-step means to rotate the member, solenoid means to move the step-by-step means in one direction, spring means to move it in the opposite direction, switch means operated by the movement ofthe step-by-step means to alternately energize and deenergize the solenoid means, and switching means actuated by therotation of the member in series with the first-named switching means to cause the member to stop at the desired index.

K switching means to cause the member to stop at a conducting ring having a slot therein carried 15 the desired index, and a plurality of switches in parallel connected to the switching means vactuated by the rotation o f the member to individually initiate an energizing circuit.

LUDWIG J. FIGHTER. BERTRAM A sCHwARa 

